Apparatus for the separation of minerals by flotation.



Patented Nov. 26, 1918,

IHIHHH l H mun wing F. D. S. ROBERTSON.

APPARATUS FOR THE SEPARATION o MINERALS BY FLOTATION. APPLICATION FILED DEC. 5. I917.

I'IIII HHHA.

Ill-"- JNVENZUH. -Wig FREDERICK D. S. ROBERTSON, OF TORONTO, ONTARIO, CANADA.

APPARATUS FOR THE SEPARATION OF MINERALS BY FLOTATION.

Specification of Letters Patent.

Patented Nov. 26, 1918.

Application filed December 5, 1917. Serial No. 205,641.

T 0 all whom it may concern.-

Be it known that I, FREDERICK D. S. Ron- ERTSON, of the city of Toronto, in the county of York, Province of Ontario, Canada, have invented certain new and useful Improve-. ments in Apparatus for the Separation of Minerals by Flotation, of which the following is a specification. v

This invention relates to the separation of the valuable constituents of ore from the gangue and from one another by takin ad.- vantage of differences in their fioatability, and my object is to devise an apparatus for separating minerals which will result in a very complete separation'combined with a high rateof output.

I attain my object by causing flotation to take place on a moving table to which preferably both a gyratory and a rotary motion. are imparted, floating materials passing off the periphery of the table and sinking ma: terial being withdrawn adjacent the center. The process is hereinafter more specifically described and the apparatus illustrated in the accompanying drawings in which' Figure 1 is a vertical section of the apparatus employed in my process; and

Fig. 2 a plan view of the same partly in section. In the drawings like numerals of reference indicate corresponding parts in the different figures.

1 is the frame of the apparatus suitably shaped to support the different parts. J ournaled in suitable hearings in this frame is a\ vertical shaft 2, preferably hollow for a purpose which will hereafter appear. This shaft has a crank 7 formed therein intermediateits ends with a throw of approximately from one to two inches. On this crank is journaled a sleeve 3, to which is secured a pan 4, preferably dished as shown. With a crank throw off from one to two inches, this an will probably be from ten to twelve feet in diameter.

Secured to the sleeve 3 is a pulley 5. A driving pulley 6 is secured to the shaft 2. It is evident that if the shaft only be driven while the pulley 5 is held from rotation that a gyratory movement only will be imparted to the pan 4, that is, any point on its surface will move in a circle whose radius is equal to the throw of the rank 7. If the pulley 5 be driven, it is evident that the pan will have a rotary movement only, any point on its surface moving in a circle about the axis of the crank. By driving both pulleys, any desired combination of rotary and gyratory motion may be imparted to the pan. Thus, If desired, a high rate of rotation may be combined with a low rate of gyration or vice versa.

It is necessary to rovide means for driving the pulley 5, wliose operation will not be interfered with by the movement of the crank. I illustrate the following mechanism for this purpose. A countershaft 8 is journaled on the frame and'suitably driven. This countershaft is provided with a pulley belted to the pulley 5 and a pulley 10 belted to the pulley (5. An idler 11 engages one side of the belt and is yieldingly' pressed into contact With the same. I show it as journaled on an arm 12 pivoted at its lower end on the frame. To this arm is secured one end of a coil spring 13, the other end of which is secured to the frame. care of the alternate slackening and tightening of the belt due to the gyratory movement of the pulley 5.

In order to feed the pulp on to the pan I provide the upper end of the hollow shaft with a hopper 1 1, and close the hollow shaft just above the crank with a partition 15. Through the side of the shaft a series of holes 16 are made and to the shaft below the holes is secured a conical plate 17, the lower edge of which is comparatively close to the upper edge of the pan.

Near the crank holes 18 are formed in the pan, with which preferably communicate the discharge tubes 19 leading through the pulley 5. Below the pulley holes 20 are formed leading into the interior of the shaft, and the catch pan 21 is secured to the shaft just below these holes. Any material passing through the tubes 19 is thus caught in the pan and discharged through the lower part of the hollow shaft.

To catch material passing over the outer edge of the pan I provide the large tray 22 secured to the frame, provided with a discharge spout 23.

The operation of the apparatus is asfollows:

Having by experiment determined the rate of rotation and rate of oscillation which will give the best results with the particular ore being operated on, the proportions of the pulleys are determined and the proper sizes employed in the apparatus. The apparatus is then set in motion and pulped ore fed at a This idler will take the outer edge of the pan and fall into the tray 22, while the heavier minerals and ganguedrift toward the center of the panand escape through the holes 20, thence down .into the catch pan 21 and out through the lower end of the hollow shaft.

While the rates of rotation and-oscillation must be determined by experiment for each particular ore, the general rule will be thatthe rate of rotation must not be so great as to interfere with the movement of the heavier constitutents of the ore toward the center under the influence of gravity and of that proportion of the Water in the pulp which flows toward the center instead of over the outer edge.

Any suitable devices may be employed at any point as is common in the art to facilitate or hasten the movements of the partiticles of the ore. While for many purposes a smooth surfaced pan will satisfactorily answer my purposes, yet the surface may be roughened or provided with rifiles of various kinds as is common in classifying tables.

It will be seen that the apparatus takes up but little head room, so that several tables may readily be arranged in series one above the other so that the tailings from one may be re-treated to recover floatable constituents of the ore not properly separated by a single treatment.

What I claim as my invention is '1. Apparatus for concentrating ores comprising a dished table; a vertical crank shaft on the crank of which the table is journaled; means for rotating the shaft; a pulley secured to the table concentric with the crank; discharge tubes from the center part ofthe table extending through the pulley for rotating the table; means for feeding pulp on tubes; and a stationary tray adapted to receive the material passing over the rim of a the table. v o

2. Apparatus for concentrating ores comprising a table; a vertical crank shaft on the crank of which the table is journaled; a pulley secured to the shaft; a pulley secured to the table concentric with the crank; a countershaft; pulleys thereon boltedto the pulleys aforesaid; discharge tubes from the center part'of the table extending through the pulley for rotating the table; means for feeding pulp on to the table intermediate said discharge tubes and the rim of the table; a catch pan supported to catch the discharge from said tubes; and a stationary tray adapted to receive the material passing over the rim of the table.

3. Apparatus for concentrating ores comprising a table; a vertical hollow crank shaft on the crank of which the table is journa'led, said shaft having apertures formed in its wall above the table and a partition below said apertures; a conical feed plate or apron secured to said shaft just below said apertures; means for withdrawing sinking constituents at or near the center of'the table; means for rotating the shaft; and means for rotating the table on the crank.

4. Apparatus for concentrating ores comprising a table; a vertical hollow crank shaft on the crank of which the table is journaled, said shaft having apertures formed inits wall above the'table and a partition below said apertures; a conical feed plate or apron secured to said shaft just below said apertures; discharge tubes from the center part of the table extending through the pulley for rotating the table; a catch pan secured to the V shaft below said pulley, holes being pro* videdin the wall of the shaft through which the catch pan may discharge into the hollow shaft; means for rotating the shaft; and means for rotating the table on the crank.

Signed at Toronto this23rd day of Nov, A. D. 1917.

FREDERICK D. S. ROBERTSON. 

